The statements in this section merely provide background information related to the present invention and may or may not constitute prior art.
LCD (liquid crystal display) TV, PC, Monitors, display devices are widely used. In general, a LCD module comprises three main assemblies, i.e. a backlight module, a LCD panel and a front frame. The backlight module comprises a back cover, a positioning assembly and a backlight assembly. The backlight assembly may comprise reflecting sheet, a light guiding plate and optical membranes. The reflecting sheet, the light guiding plate and the optical membranes (optical films) are fixed by four positioning components located at the four corner of the back cover respectively. As shown in FIG. 1, the end portions of the positioning components 104 are provided with a hook 101. By means of the hook 101 the positioning components 104 is connected to the back cover 108. Furthermore, the light guiding plate 106 is positioned by the stepping portions of the positioning components 104. And the positioning components 104 are provided with pins 105 and the optical membranes 103 are provided with holes. The pins 105 penetrate through the holes on the optical membranes 103 so as to guarantee the mechanical strength of the optical membranes 103. In this way, the optical membranes 103 are fixed on by the positioning components 104 securely. Since the light guiding plate 106 may expand when it is heated, the positioning components 104 is usually formed of elastic material such as rubber. However, the light guiding plate 106 may expand and exert pressure on other parts (such as the light bar of the backlight module). There is a risk that the other parts will be compressed and damaged by the light guiding plate.